This project will utilize basic laboratory research methodology to evaluate the cross-species generality to humans of two behavioral- pharmocological principles which have been derived from animal laboratory research. The two principles are: (1) effects of several drugs on behavior are substantially determined by the rate of occurrence of that behavior (rate-dependency); (2) certain drugs have selective effects on behavior suppressed by punishment -- some drugs restore punished responding to high rates, while other further decrease already low rates of punished responding. Dose-response relations will be determined in normal human subjects for behavioral effects of d-amphetamine, chlordiazepoxide and chlorpromazine on patterns of operant switch-closure or vocal responding maintained under schedules of reinforcement and/or punishment.